Burundi President Pierre Nkurunziza and opposition politicians have agreed to hold talks to end a 10-month-old crisis, U.N. Secretary General Ban Ki-moon said Tuesday.

After meeting with Nkurunziza and government and opposition politicians, Ban said that all sides had agreed to "inclusive dialogue" and that the president "confirmed, that he would engage in political dialogue."

At least four people were killed in fresh attacks ahead of U.N. Secretary General Ban Ki-moon's arrival in Bujumbura Monday, his first visit to Burundi since a crisis began in April last year.

Ban, who landed late on Monday afternoon, is due to hold talks with President Pierre Nkurunziza on Tuesday after meeting with leaders of political parties and civil society aimed at giving fresh impetus to stalled efforts at resolving the 10-month-old crisis.

Burundi banned motorbikes from the center of the capital Bujumbura on Tuesday after a string of grenade attacks by insurgents on motorcycles, the mayor said.

On Monday, men on bikes threw three grenades in the heart of the city, while two other blasts were reported in a northern suburb, killing at least one child and wounding scores.

Two people loyal to the ruling party in troubled Burundi were "executed" overnight in the center of the country, a local official and witnesses said Saturday.

Burundi has been in crisis since April when President Pierre Nkurunziza ran for and won a controversial third term, sparking street protests, a failed coup, regular killings and a nascent rebellion.

Twenty-six people were injured, nine of them seriously, when a grenade exploded Thursday in the Burundi capital of Bujumbura, local police said.

The grenade was thrown onto a crowded street in the city's Buyenzi district by a man on a motorbike, witnesses and a journalist said.

African Union efforts to approve a peacekeeping force for troubled Burundi faced tough challenges as leaders met ahead of an unprecedented vote on the potential deployment of 5,000 troops.

Talks at the AU Peace and Security Council, attended by presidents and foreign ministers from across the 54-member bloc as well as U.N. Secretary General Ban Ki-moon, stretched late into Friday night in a bid to narrow positions before the opening of a summit meeting on Saturday.

The French government, Agence France-Presse (AFP) and Le Monde newspaper on Friday demanded that Burundi immediately free a French journalist and a British photographer arrested while reporting in the volatile central African nation.

"We were concerned to learn of the arrests of French journalist Jean-Philippe Remy and British photographer Philip Moore," Foreign Minister Laurent Fabius said in a statement.

The African Union said Thursday it was determined to end the crisis in Burundi as it readies for a key summit where leaders face an unprecedented vote on deploying a 5,000-strong peacekeeping force.

Burundi vehemently opposes any outside military force, but Aisha Abdullahi, AU Commissioner for Political Affairs, said she was "optimistic" it would be pushed through.

U.N. Security Council ambassadors met Burundi's leaders on Friday to push peace efforts after another night of violence in the capital of the troubled central African nation.

The visit is the council's second to Burundi in less than a year, with ambassadors set to deliver a face-to-face message to President Pierre Nkurunziza to take urgent action to stop the violence sparked by his re-election bid.

U.N. Security Council ambassadors headed to Burundi on Wednesday to push the government to open up serious talks with the opposition and agree to an African Union force that could prevent a slide to all-out war.

It is the second time in less than a year that the 15-member council travels to Burundi, where the United Nations has warned that months of violence could escalate into ethnic killings and mass atrocities.